It is a standard practice in the industrialized world to disinfect the skin prior to any invasive procedure such as surgery, catheterization, or needle puncture to reduce the risk of infection. Currently, chlorhexidine compositions are an agent of choice for disinfecting hands, skin, surgical sites, catheter sites, and oral cavities. Chlorhexidine and its salts are well-known antimicrobials with excellent efficacy that are safe to use. Chlorhexidine and its salts also show persistent antimicrobial activity on the skin often for more than 24 hours.
Two hydroalcoholic compositions containing chlorhexidine are currently available. AVAGARD surgical hand prep is a hydroalcoholic composition containing 1% chlorhexidine gluconate in 61% ethanol available from 3M Company. CHLOROPREP surgical prep is a composition containing 2% w/v chlorhexidine gluconate (CHG), 70% v/v isopropanol, and water available from Mediflex, Inc.
Products that contain chlorhexidine or its derivatives suffer from several disadvantages. Chlorhexidine is a cationic bisguanide, which can be readily deactivated by salts (chlorides, carbonates, and the like), nonionic surfactants, anionic surfactants, and anionic compounds such as organic acids or salts of organic acids. Many soaps and skin creams contain these agents and readily deactivate chlorhexidine and its salts. Chlorhexidine compositions can also be irritating to skin and mucous membranes. Products that contain greater than 2% CHG can cause significant irritation, particularly after repeated use.
Surgical preps containing chlorhexidine and/or other antimicrobials can undermine the adhesion of medical tapes, dressings, and surgical drapes, particularly under wet skin conditions. Chlorhexidine salts in particular exacerbate this problem because they are hydrophilic and sit on the surface of the skin after topical application. Under wet conditions, such as in surgery when large amounts of body fluids or saline are present, the chlorhexidine salts can cause the loss of adhesion of surgical drapes and dressings. This adhesion loss is often called “drape lift” and is highly undesirable because it can interrupt the sterile field, which increases the probability of a surgical site infection.
There is a clear need for chlorhexidine compositions which have low irritation, cosmetic acceptability, excellent efficacy, and improved wet adhesion for use in surgical and catheter sites.